Natural abundance and background of cadmiun in river water, soil and rice grain in Japan

从人体健康和环境污染的角度来看，镉和汞可能是最关键的元素。特别是日本，其肾皮质和日摄入量中镉的浓度是被调查国家中最高的，申报流水、土壤和农产品中镉的自然丰度和本底范围可能更为重要，以便制定一些有效的措施来防止镉在环境和人体中的积累。对土壤和农产品的正确消解方法进行了技术检查，并对消化液进行了前处理，用电感耦合等离子体质谱(ICMS)检测元素的ppt水平。HNO3和HCl等超纯试剂当然可以有效地减少检测过程中的污染物，但对镉的检测并不是必需的。采用螯合滤膜进行前处理，可以有效地去除干扰重金属元素ppt测定的主要基质元素碱土和碱土元素。在此基础上，对日本各地河水、地下水、温泉水、不同类型母岩来源的土壤、不同类型土壤中的稻谷等大量样品进行了镉含量检测。

Cadmium and mercury might be most critical elements from view point of human health and environmental pollution. Particularly for Japanese whose cadmium concentration in kidney cortex and daily intake had been proved to be highest among the surveyed countries, it may be much more important to declare the range of natural abundance and background of cadmium in running river water, soil and agricultural products in order to establish some effective measure to prevent accumulation of cadmium in environment and human body.Technical check had been done about proper method of digestion of soil and agricultural product, and pretreatment of the digested solution for detection of ppt level of elements with ICP MS.Ultra-pure reagents as HNO_3 and HCl were of course effective to reduce the contaminants during the procedure but not essential for detection of cadmium. Pretreatment with Chelate Filter was very much useful to remove alkali and alkali earth elements which are major matrix elements disturbing detection of ppt level of heavy metal elements.Based on the technical check above written, cadmium levels in large number of samples as river waters, ground waters, hot spring waters, varieties of soils originated from different types of parent rocks, and rice grains produced on different types of soils all over Japan were detected.